U.S. patent application number 13/851842 was filed with the patent office on 2013-08-15 for method for manufacturing photoelectric conversion device, solid-state imaging device and imaging apparatus.
This patent application is currently assigned to FUJIFILM CORPORATION. The applicant listed for this patent is FUJIFILM CORPORATION. Invention is credited to Yuki KURAMOTO, Tetsuro MITSUI.
Application Number | 20130206966 13/851842 |
Document ID | / |
Family ID | 45892545 |
Filed Date | 2013-08-15 |
United States Patent
Application |
20130206966 |
Kind Code |
A1 |
MITSUI; Tetsuro ; et
al. |
August 15, 2013 |
METHOD FOR MANUFACTURING PHOTOELECTRIC CONVERSION DEVICE,
SOLID-STATE IMAGING DEVICE AND IMAGING APPARATUS
Abstract
Also provided is a method for manufacturing a photoelectric
conversion device including: a first process where a plurality of
pixel electrodes 104 are formed on a dielectric layer 102; a second
process where a light receiving layer 107 that includes an organic
material is formed on the plurality of pixel electrodes 104; and a
third process where a counter electrode 108 is formed on the light
receiving layer 107, in which the first process comprises: a film
forming process of a pixel electrode material on the dielectric
layer 102; a patterning process of the film of the pixel electrode
material; and a heating process for heating the substrate at
270.degree. C. after the patterning process.
Inventors: |
MITSUI; Tetsuro;
(Ashigarakami-gun, JP) ; KURAMOTO; Yuki;
(Minami-Ashigara-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJIFILM CORPORATION; |
|
|
US |
|
|
Assignee: |
FUJIFILM CORPORATION
Tokyo
JP
|
Family ID: |
45892545 |
Appl. No.: |
13/851842 |
Filed: |
March 27, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2011/068193 |
Aug 9, 2011 |
|
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13851842 |
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Current U.S.
Class: |
250/208.1 ;
438/98 |
Current CPC
Class: |
H01L 27/307 20130101;
H01L 27/146 20130101; H01L 31/18 20130101 |
Class at
Publication: |
250/208.1 ;
438/98 |
International
Class: |
H01L 31/18 20060101
H01L031/18; H01L 27/146 20060101 H01L027/146 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2010 |
JP |
2010-216104 |
Aug 2, 2011 |
JP |
2011-169649 |
Sep 27, 2011 |
JP |
2011-211330 |
Claims
1. A method for manufacturing a photoelectric conversion device
which comprises: a first electrode containing a conductive
material, the first electrode formed on a dielectric film composed
of an oxide film, which is formed on a substrate; a light receiving
layer which includes an organic material formed on the first
electrode; and a second electrode formed on the light receiving
layer, wherein the method for manufacturing the photoelectric
conversion device comprises: a first process for forming the first
electrode on the dielectric film; a second process for forming the
light receiving layer on the first electrode; a third process for
forming the second electrode on the light receiving layer; and a
heating process for heating the substrate at 270.degree. C. or
above, the heating process performed before the second process and
after the first process.
2. The method for manufacturing the photoelectric conversion device
of claim 1, wherein the first process comprises: a film forming
process of a conductive material on the dielectric film; and a
patterning process of a formed film of the conductive material.
3. The method for manufacturing the photoelectric conversion device
of claim 2, wherein the patterning process is performed in a
vacuum.
4. The method for manufacturing the photoelectric conversion device
of claim 2, wherein the patterning process is performed by
photolithography and etching.
5. The method for manufacturing the photoelectric conversion device
of claim 1, wherein the light receiving layer includes: an electric
charge blocking layer that includes an organic material; and a
photoelectric conversion layer that includes an organic layer.
6. The method for manufacturing the photoelectric conversion device
of claim 1, wherein the conductive material is ITO or TiON.
7. The method for manufacturing the photoelectric conversion device
of claim 6, wherein the conductive material is TiON, and atomic %
of an oxygen amount contained in the first electrode to a titanium
amount is increased by 10% or more before and after the heating
process.
8. A solid-state imaging device comprising: the photoelectric
conversion device manufactured by the method for manufacturing the
photoelectric conversion device of claim 1; and a signal reading
circuit formed on the substrate, the signal reading circuit capable
of reading out the signal according to a quantity of electric
charges collected in the first electrode.
9. An imaging apparatus comprising the solid-state imaging device
of claim 8.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for manufacturing
a photoelectric conversion device, a solid-state imaging device and
an imaging apparatus.
BACKGROUND ART
[0002] For a conventional solid-state imaging device having a
photodiode in a semiconductor substrate, minimization of a pixel
size reaches its limit, making it difficult to improve performance
such as sensitivity and the like. Accordingly, there has been
suggested a solid-state imaging device which is highly sensitive
stack type, and enables to obtain 100% aperture ratio by installing
a photoelectric conversion layer on the upper part of a
semiconductor substrate (Patent Document 1).
[0003] The stack type solid-state imaging device as disclosed in
Patent Document 1 has a constitution where a plurality of pixel
electrodes are arrayed on the upper part of a semiconductor device,
a light receiving layer which includes an organic material
(including at least a photoelectric conversion layer) is formed on
the upper part of the plurality of pixel electrodes, and a counter
electrode is formed on the upper part of the light receiving layer.
The solid-state imaging device applies an electric field to the
light receiving layer by applying a bias voltage to the counter
electrode, and transfers the electric charge generated in the light
receiving layer to the pixel electrode. Then, the stack type
solid-state imaging device reads out a signal corresponding to the
electric charge by a reading circuit which is connected to the
pixel electrode.
[0004] In the stack type solid-state imaging device, after a pixel
electrode, a light receiving layer and a counter electrode are
formed, a protective film, a color filter, other functional films
and the like may be formed on the upper part thereof in some cases
so as to block the outside air (water and oxygen). In the case of a
color filter, for example, along with a process of applying
chemicals, a heating process is generally performed at 200.degree.
C. with respect to the light receiving layer for curing.
[0005] In addition, the heating process is also performed in cases
of wire bonding for electrically connecting a circuit board and a
package, a die bonding of a chip for package and reflow soldering
for connecting a package to an IC substrate. Further, for the wire
bonding, it is required to install a PAD opening on the periphery
of a chip and the like, and in this case, forming a registor
pattern or etching is performed, and at each process, heating
process is performed for the substrate where a light receiving
layer is formed.
[0006] As described above, in the case of manufacturing a
solid-state imaging device using a light receiving layer that
includes an organic material, a high-temperature heating process is
required when adopting a processing method used in a conventional
silicon device. A light receiving layer is required to be resistant
to such heating process.
[0007] As a method for improving heat resistance of a light
receiving layer, it is common to use a material having a little
heat change (for example, a material having a high glass transition
Tg). However, a light receiving layer is also required to have
properties such as high photoelectric conversion efficiency and a
low dark current, in addition to heat resistance. Accordingly, it
is necessary to choose a material that satisfies those properties
and heat resistance, which narrows the choice range of a material
of a light receiving layer.
[0008] As described above, many methods have been suggested to
improve heat resistance of a light receiving layer. However, it has
not been known to improve heat resistance with the focus on other
constituent elements than a light receiving layer.
[0009] Further, not only a solid-state imaging device, but also
other devices such as a solar cell using a light receiving layer
have the problem of heat resistance if the heating process is
performed after a light receiving layer is formed.
[0010] Patent Documents 2 and 4 disclose a method for manufacturing
a photoelectric conversion device in which an ITO film is formed on
a glass substrate by a sputtering method, and after patterning is
performed to form a pixel electrode, the substrate is heated and
dried at 250.degree. C., and then a light receiving layer and a
counter electrode are formed.
[0011] However, the manufacturing method only provides heating at
250.degree. C. for drying the ITO pixel electrode, without the aim
of improving heat resistance. In addition, the method does not
describe the specific range of temperatures for improving heat
resistance of a photoelectric conversion device having a light
receiving layer that includes an organic material.
[0012] Moreover, Patent Document 5 describes a thin film solar cell
in which after Ag electrode is formed on a polyimide substrate,
heating is performed at 230.degree. C. before forming an a-Si
photoelectric conversion layer.
[0013] However, the method relates to an inorganic solar cell, and
does not describe the specific range of temperatures for improving
heat resistance of a photoelectric conversion device having a light
receiving layer that includes an organic material.
RELATED ART
Patent Document
[0014] Patent Document 1: Japanese Patent Application Laid-Open No.
2008-263178 [0015] Patent Document 2: Japanese Patent Application
Laid-Open No. 2005-085933 [0016] Patent Document 3: Japanese Patent
Application Laid-Open No. 2008-072435 [0017] Patent Document 4:
Japanese Patent Application Laid-Open No. 2008-072589 [0018] Patent
Document 5: Japanese Patent Application Laid-Open No.
2001-007367
DISCLOSURE OF INVENTION
Problems to be Solved by the Invention
[0019] The present invention has been made in consideration of the
aforementioned circumstances, and for a photoelectric conversion
device having a light receiving layer that includes an organic
material, the object of the present invention is to provide a
method for manufacturing a photoelectric conversion device capable
of improving heat resistance irrespective of a material of a light
receiving layer. Further, it is another object of the present
invention to provide a solid-state imaging device that includes a
photoelectric conversion device manufactured by the manufacturing
method, and an imaging apparatus that includes the solid-state
imaging device.
Means for Solving the Problems
[0020] The present invention relates to a method for manufacturing
a photoelectric conversion device which includes: a first electrode
in which a dielectric film composed of an oxide film is formed on a
substrate, the first electrode which includes a conductive material
formed on the dielectric film; a light receiving layer that
includes an organic material formed on the first electrode; and a
second electrode formed on the light receiving layer, in which the
method includes: a first process for forming the first electrode on
the dielectric film; a second process for forming the light
receiving layer on the first electrode; a third process for forming
the second electrode on the light receiving layer; and a heating
process for heating the substrate at 270.degree. C. or above, the
heating process performed before the second process and after the
first process.
[0021] The solid-state imaging device of the present invention is
provided with the photoelectric conversion device manufactured by
the aforementioned method for manufacturing the photoelectric
conversion device, and a signal reading circuit that is formed on
the substrate and reads out a signal corresponding to a quantity of
electric charges generated in the light receiving layer and
collected in the first electrode.
[0022] The imaging apparatus of the present invention includes the
solid-state imaging device.
Advantageous Effects of Invention
[0023] According to the present invention, in the photoelectric
conversion device having the light receiving layer that includes an
organic material, it is possible to provide a method for
manufacturing the photoelectric conversion device capable of
improving heat resistance irrespective of a material of the light
receiving layer. Further, it is possible to provide a solid-state
imaging device having the photoelectric conversion device
manufactured by the manufacturing method and an imaging apparatus
having the solid-state imaging device.
BRIEF DESCRIPTION OF DRAWINGS
[0024] FIG. 1 is a cross-sectional view schematically illustrating
the constitution of a solid-state imaging device according to an
exemplary embodiment of the present invention.
[0025] FIG. 2 is a cross-sectional view illustrating the preferred
example of a light receiving layer in the solid-state imaging
device shown in FIG. 1.
EMBODIMENTS FOR CARRYING OUT THE INVENTION
[0026] Hereinafter, the present invention will be described in
detail with reference to drawings.
[0027] After inventors' review of the improvement of heat
resistance for the photoelectric conversion device having a pixel
electrode formed on the upper part of the substrate, a light
receiving layer including an organic material and formed on the
pixel electrode and a counter electrode formed on the light
receiving layer, it was found out that by performing a substrate
heating process at 270.degree. C. or above before forming the light
receiving layer and after the pixel electrode is formed, heat
resistance of the photoelectric conversion device is improved
irrespective of a constitution of the light receiving layer.
[0028] Further, in the substrate heating process, the upper limit
of the substrate heating temperature is 800.degree. C. When the
temperature exceeds the limit, in the case where oxygen is present
in the environment of the heating process, the pixel electrode
reacts with oxygen, and as a result, the pixel electrode becomes an
insulator. More preferred range of heating temperature is from
280.degree. C. to 800.degree. C., and still more preferred range is
from 350.degree. C. to 800.degree. C.
[0029] Although the reason why the substrate heating process
improves heat resistance is not obvious, it is assumed that when
forming the light receiving layer without performing the substrate
heating process, the pixel electrode, which acts on the light
receiving layer in the heating process later performed for the
photoelectric conversion device, is deteriorated, and as a result,
performance is deteriorated.
[0030] Further, the heating process which is performed later for
the photoelectric conversion device refers to a color filter
curing, wire bonding, die bonding and reflow soldering which are
performed after the counter electrode is formed, and a high
temperature heating process (generally a heating process at
200.degree. C. to 220.degree. C.) which is performed when a PAD
opening is formed.
[0031] In the heating process which is performed later for the
photoelectric conversion device, it is assumed that oxygen is
introduced from an oxide film under the pixel electrode (for
example, an SiO.sub.2 film) to the pixel electrode. As a result,
the light receiving layer is affected by a very small amount of gas
flowing from the pixel electrode and the like, which accelerates
deformation of the light receiving layer and generates a leakage,
or changes a composition of the pixel electrode such that
electrical connection of the pixel electrode and the light
receiving layer is changed, thereby deteriorating heat
resistance.
[0032] Further, it is also assumed that in the film forming process
of a pixel electrode material or a patterning process of a pixel
electrode (photolithography and etching process), contamination
components (for example, residual components such as gas used in an
organic solvent or a film forming process), which are adsorbed or
introduced on the surface or inner side of the pixel electrode, are
volatilized from the surface or inner side of the pixel electrode
in the heating process performed later for the photoelectric
conversion device, thereby having an adverse effect on the light
receiving layer formed on the pixel electrode, and deteriorating
heat resistance.
[0033] It is thought that in the case of having the substrate
heating process, gas or contamination components, which adversely
affect the light receiving layer, can be volatilized in advance
from the surface and inner side of the pixel electrode. As a
result, in the heating process performed later for the
photoelectric conversion device, leakage of gas from the pixel
electrode or volatilization of contamination components from the
pixel electrode are prevented, thereby improving heat resistance of
the photoelectric conversion device.
[0034] Hereinafter, an exemplary embodiment of the solid-state
imaging device using the photoelectric conversion device having the
light receiving layer that includes an organic material will be
described.
[0035] FIG. 1 is a cross-sectional view schematically illustrating
the constitution of a solid-state imaging device according to an
exemplary embodiment of the present invention. The solid-state
imaging device is used by being mounted in the imaging apparatus
such as a digital camera, a digital video camera, an electronic
endoscope apparatus and a mobile phone with a camera.
[0036] A solid-state imaging device 100 illustrated in FIG. 1
includes a substrate 101, a dielectric layer 102, a connection
electrode 103, a pixel electrode 104, a connection portion 105, a
connection portion 106, a light receiving layer 107, a counter
electrode 108, a buffer layer 109, a sealing layer 110, a color
filter 111, a partition wall 112, a light-shielding layer 113, a
protection layer 114, a counter electrode voltage supply portion
115 and a reading circuit 116.
[0037] The substrate 101 is a glass substrate or a semiconductor
substrate such as Si. The dielectric layer 102, which is composed
of silicon oxide, is formed on the substrate 101. A plurality of
pixel electrodes 104 are formed side by side on the surface of the
dielectric layer 102. The connection portion 105 is formed in the
dielectric layer 102 to correspond to each of the plurality of
pixel electrodes 104.
[0038] The light receiving layer 107 is a layer that includes an
organic material and is constituted by at least a photoelectric
conversion layer. The photoelectric conversion layer generates
electric charges according to the received light. The light
receiving layer 107 is provided to cover the plurality of pixel
electrodes 104 and formed thereon. The light receiving layer 107 is
formed in a predetermined thickness, but the thickness may be
changed in a region other than an effective pixel region where the
pixel electrodes 104 are disposed. The light receiving layer 107
will be described in detail below. Further, the light receiving
layer 107 includes not only a layer which is composed only of an
organic material, but also a layer a part of which is composed of
an inorganic material.
[0039] The counter electrode 108 is an electrode facing the pixel
electrodes 104, and is installed on the light receiving electrode
107 to cover the light receiving electrode 107. The counter
electrode 108 is formed up to the top of the connection electrode
103 disposed at the outer side of the light receiving layer 107 and
is electrically connected to the connection electrode 103.
[0040] The counter electrode 108 is preferably composed of a
transparent conductive film to allow light to be incident on the
light receiving layer 107 that includes the photoelectric
conversion layer. Examples of the material of the transparent
conductive film may include metal, metal oxides, metal nitrides,
metal borides, an organic conductive compound, a mixture thereof
and the like.
[0041] Specific examples thereof may include conductive metal
oxides such as tin oxide, zinc oxide, indium oxide, indium tin
oxide (ITO), indium zinc oxide (IZO), indium tungsten oxide (IWO),
and titanium oxide, metal nitrides such as titanium nitride (TiN),
metal such as gold (Au), platinum (Pt), silver (Ag), chromium (Cr),
nickel (Ni), aluminum (Al), mixtures or laminates of the metals and
the conductive metal oxides, organic conductive compounds such as
polyaniline, polythiophene, and polypyrrole, laminates of the
organic conductive compounds and ITO and the like.
[0042] Particularly preferable examples of the material of the
transparent conductive film include any one material of ITO, IZO,
TiN, tin oxides, antimony-doped tin oxides (ATO), fluorine-doped
tin oxides (FTO), zinc oxides, antimony-doped zinc oxides (AZO) and
gallium-doped zinc oxides (GZO).
[0043] The connection portion 106 is buried in the dielectric layer
102. The connection portion 106 is composed of a plug and the like
to electrically connect the connection electrode 103 and the
counter electrode voltage supply portion 115.
[0044] The counter electrode voltage supply portion 115 is formed
on the substrate 101. The counter electrode voltage supply portion
115 applies a predetermined voltage to the counter electrode 108
through the connection portion 106 and connection electrode
103.
[0045] In the case where the voltage to be applied to the counter
electrode 108 is higher than a power voltage of the solid-state
imaging device 100, the counter electrode voltage supply portion
115 supplies a predetermined voltage by increasing a power voltage
by a voltage increasing circuit such as a charge pump.
[0046] The pixel electrode 104 is an electrode for collecting
electric charges generated in the light receiving layer 107 which
is interposed between the pixel electrode 104 and the counter
electrode 108 facing the pixel electrode. The pixel electrode 104
is composed of a conductive material. Examples of the material of
the pixel electrode 104 may include at least any one of TiN
(titanium nitride), TiON (titanium oxide nitride), W, Cr, ITO, Al,
Cu, AlCu. Particularly preferable material is ITO, TiON and
TiN.
[0047] The reading circuit 116 is installed on the substrate 101 to
correspond to each of the plurality of pixel electrodes 104, and
reads out the signals according to the electric charges collected
in the corresponding pixel electrode 104.
[0048] The reading circuit 116 is constituted by, for example, a
CCD, an MOS circuit or a TFT circuit, and is light-shielded by a
light-shielding layer (not shown) disposed in the dielectric layer
102. The reading circuit 116 and the pixel electrode 104
corresponding thereto are electrically connected through the
connection portion 105.
[0049] The buffer layer 109 is formed on the counter electrode 108
to cover the counter electrode 108.
[0050] The sealing layer 110 is formed on the buffer layer 109 to
cover the buffer layer 109.
[0051] The color filter 111 is formed at a position facing each of
the pixel electrodes 104 on the sealing layer 110.
[0052] The partition wall 112 is installed between the color
filters 111 to improve light transmittance efficiency of the color
filters 111.
[0053] The light-shielding layer 113 is formed in a region other
than a region where the color filter 111 and the partition wall 112
are installed on the sealing layer 110. The light-shielding layer
113 prevents light from being incident on the light receiving layer
107 formed in a region other than an effective pixel region.
[0054] The protection layer 114 is formed on the color filter 111,
the partition wall 112 and the light-shielding layer 113, and
protects the entire solid-state imaging device 100.
[0055] Further, in FIG. 1, the pixel electrode 104 and the
connection electrode 103 are buried in the surface portion of the
dielectric layer 102, but the pixel electrode 104 and the
connection electrode 103 may be formed on the dielectric layer
102.
[0056] In addition, the connection electrode 103, the connection
portion 106 and the counter electrode voltage supply portion 115
are installed as a plurality of sets, but only one set thereof may
be installed. As illustrated in FIG. 1, a voltage drop in the
counter electrode 108 may be suppressed by supplying voltage from
both ends of the counter electrode 108 to the counter electrode
108. The number of sets may be increased or decreased in
consideration of a chip size of a device.
[0057] Hereinafter, a preferred constitution of the light receiving
layer will be described.
[0058] FIG. 2 is a cross-sectional view illustrating an exemplary
embodiment of the light receiving layer 107. As illustrated in FIG.
2, the light receiving layer 107 includes an electric charge
blocking layer 107b which is installed at the side of the pixel
electrode 104, and a photoelectric conversion layer 107a which is
installed thereon. The position of the electric charge blocking
layer 107b and that of the photoelectric conversion layer 107a may
be reversed.
[0059] The electric charge blocking layer 107b has a function of
suppressing dark current. The electric charge blocking layer may be
constituted by a plurality of layers. By having the electric charge
blocking layer constituted by a plurality of layers, an interface
is formed between the plurality of electric charge blocking layers.
As discontinuity occurring at a mid-level present in each layer
makes it difficult to move electric charge carriers through the
mid-level, it is possible to strongly suppress the dark
current.
[0060] The photoelectric conversion layer 107a includes a p-type
organic semiconductor and an n-type organic semiconductor. By
forming a donor-acceptor interface with the junction of p-type
organic semiconductor and an n-type organic semiconductor, it is
possible to increase an exciton dissociation efficiency.
Accordingly, the photoelectric conversion layer 107a having a
junction of the p-type organic semiconductor and the n-type organic
semiconductor exhibits a high photoelectric conversion efficiency.
Specifically, the photoelectric conversion layer 107a having a
combination of the p-type organic semiconductor and the n-type
organic semiconductor is preferable in that a junction interface is
increased and photoelectric conversion efficiency is improved.
[0061] The p-type organic semiconductor (compound) is a donor-type
organic semiconductor, mainly represented by a hole transporting
organic compound, and an organic compound having a property of
easily donating electrons. More specifically, the p-type organic
semiconductor is an organic compound having a lower ionization
potential when two organic materials are used in contact with each
other. Accordingly, the donor-type organic compound may be any
organic compound as long as the organic compound is an
electron-donating organic compound. For example, a metal complex
having a triarylamine compound, a benzidine compound, a pyrazoline
compound, a styrylamine compound, a hydrazone compound, a
triphenylmethane compound, a carbazole compound, a polysilane
compound, a thiophene compound, a phthalocyanine compound, a
cyanine compound, merocyanine compound, an oxonol compound, a
polyamine compound, an indole compound, a pyrrole compound, a
pyrazole compound, a polyarylene compound, a condensed aromatic
carbon ring compound (a naphthalene derivative, an anthracene
derivative, a phenanthrene derivative, a tetracene derivative, a
pyrene derivative, a perylene derivative, and a fluoranthene
derivative), or a heterocyclic compound containing nitrogen as a
ligand and like may be used. Further, the examples are not limited
thereto, and any organic compound may be used as a donor-type
organic semiconductor as long as the organic compound is an organic
compound having the ionization potential that is lower than that of
the organic compound used as the n-type (acceptor-type)
compound.
[0062] The n-type organic semiconductor (compound) is an
acceptor-type organic semiconductor, mainly represented by an
electron transporting organic compound, and an organic compound
having a property of easily receiving electrons. More specifically,
the n-type organic semiconductor is an organic compound having a
higher electron affinity when two organic materials are used in
contact with each other. Accordingly, the acceptor-type organic
compound may be any organic compound as long as the organic
compound is an electron-receiving organic compound. For example, a
metal complex having a condensed aromatic carbon ring compound (a
naphthalene derivative, an anthracene derivative, a phenanthrene
derivative, a tetracene derivative, a pyrene derivative, a perylene
derivative, and a fluoranthene derivative), a 5-membered to
7-membered heterocyclic compound containing a nitrogen atom, an
oxygen atom and a sulfur atom (for example, pyridine, pyrazine,
pyrimidine, pyridazine, triazine, quinoline, quinoxaline,
quinazoline, phthalazine, sinoline, isoquinoline, pteridin,
acridine, phenazine, phenanthroline, tetrazole, pyrazole,
imidazole, thiazole, oxazole, indazole, benzimidazole,
benzotriazole, benzoxazole, benzothiazole, carbazole, purine,
triazolopyridizine, triazolopyrimidine, tetrazaindene, oxadiazole,
imidazolephridine, pyrrolidine, pyrrolopyridine,
thiadiazolopyridine, dibenzazepine, tribenzazepine and the like), a
polyarylene compound, a fluorine compound, a cyclopentadiene
compound, a silyl compound, or a heterocyclic compound containing
nitrogen as a ligand and like may be used. Further, the examples
are not limited thereto, and any organic compound may be used as an
acceptor-type organic semiconductor as long as the organic compound
is an organic compound having a higher electron affinity than that
of the organic compound used as the p-type (donor-type) organic
semiconductor.
[0063] Any organic pigment may be used as the p-type organic
semiconductor or the n-type organic semiconductor material, but
preferably, may include a cyanine pigment, a styryl pigment, a
hemicyanine pigment, a merocyanine pigment (including zeromethine
merocyanine (simple merocyanine)), a trinuclear merocyanine
pigment, a tetra-nuclear merocyanine pigment, a laudacyanine
pigment, a complex cyanine pigment, a complex merocyanine pigment,
an allophore pigment, an oxonol pigment, a hemioxonol pigment, a
squarylium pigment, a croconium pigment, an azamethine pigment, a
coumarin pigment, an arylidene pigment, an anthraquinone pigment, a
triphenylmethane pigment, an azo pigment, an azomethine pigment, a
spiro compound, a metallocene pigment, a fluorenone pigment, a
fulgide pigment, a perylene pigment, a perinone pigment, a
phenazine pigment, a phenothiazine pigment, a quinone pigment, a
diphenylmethane pigment, a polyene pigment, an acridine pigment, an
acrydinone pigment, a diphenylamine pigment, a quinacrydone
pigment, a quinaphthalone pigment, a phenoxazine pigment, a
phthaloperylene pigment, a diketopyrrolopyrrole pigment, a dioxane
pigment, a porphyrine pigment, a chlorophyll pigment, a
phthalocyanine pigment, a metal complex pigment, and a condensed
aromatic carbon ring-based pigment (a naphthalene derivative, an
anthracene derivative, a phenanthrene derivative, a tetracene
derivative, a pyrene derivative, a perylene derivative, and a
fluoranthene derivative).
[0064] As the n-type organic semiconductor, it is particularly
preferred to use a fullerene or a fullerene derivative having an
excellent electron transport property. The fullerene refers to
fullerene C.sub.60, fullerene C.sub.70, fullerene C.sub.76,
fullerene C.sub.78, fullerene C.sub.80, fullerene C.sub.82,
fullerene C.sub.84, fullerene C.sub.90, fullerene C.sub.96,
fullerene C.sub.240, fullerene C.sub.540, mixed fullerene and
fullerene nanotubes, and the fullerene derivative refers to a
compound where substituents are added thereto.
[0065] The photoelectric conversion layer 107a may include a
fullerene or a fullerene derivative to rapidly transport the
electric charges generated by photoelectric conversion via
fullerene molecules or fullerene derivative molecules to the pixel
electrode 104 or the counter electrode 108. If the fullerene
molecules or the fullerene derivative molecules are connected to
form a path of electrons, an electron transport property is
improved, thus implementing a high-speed response of the organic
photoelectric conversion device. To this end, it is preferable that
fullerene or the fullerene derivative is included in the
photoelectric conversion layer 107a at a volume ratio of 40% or
more. However, if the fullerene or the fullerene derivative is
included in an excessive amount, the amount of the p-type organic
semiconductor is reduced, and a junction interface is reduced,
thereby decreasing an exciton dissociation efficiency.
[0066] In the photoelectric conversion layer 107a, it is
particularly preferred to use a triarylamine compound as the p-type
organic semiconductor to be mixed with the fullerene or the
fullerene derivative as described in Japanese Patent No. 4213832
and the like, because it is possible to achieve a high SN ratio of
the organic photoelectric conversion device. If the ratio of
fullerene or the fullerene derivative in the photoelectric
conversion layer 107a is excessively high, the amount of the
triarylamine compound is reduced, such that an absorption quantity
of incident light is reduced. As a result, the photoelectric
conversion efficiency is reduced, and accordingly, it is preferred
that the ratio of the content of fullerene or the fullerene
derivative included in the photoelectric conversion layer 4 is 85%
by volume or less.
[0067] It is preferable that the p-type organic semiconductor used
in the photoelectric conversion layer 107a is a compound
represented by the following Formula (1).
##STR00001##
[0068] (wherein L.sub.2 and L.sub.3 each independently represent a
methine group. n represents an integer of 0 to 2. Ar.sub.1
represents a divalent substituted arylene group or an unsubstituted
arylene group. Ar.sub.2 and Ar.sub.3 each independently represent a
substituted aryl group, an unsubstituted aryl group, a substituted
alkyl group, an unsubstituted alkyl group, a substituted heteroaryl
group, or an unsubstituted heteroaryl group. Further, R.sub.1 to
R.sub.6 each independently represent a hydrogen atom, a substituted
alkyl group, an unsubstituted alkyl group, a substituted aryl
group, an unsubstituted aryl group, a substituted heteroaryl group,
or an unsubstituted heteroaryl group, and any of adjacent R.sub.1
to R.sub.6 may be bonded to each other to form a ring.)
[0069] The arylene group represented by Ar.sub.1 is preferably an
arylene group having 6 to 30 carbon atoms, and more preferably an
arylene group having 6 to 18 carbon atoms. The arylene group may be
substituted, and preferably an arylene group having 6 to 18 carbon
atoms which may have an alkyl group having 1 to 4 carbon atoms.
Examples thereof may include a phenylene group, a naphthylene
group, a methylphenylene group, a dimethylphenylene group and the
like, and a phenylene group or a naphthylene group is preferable,
and a phenylene group is more preferable.
[0070] Each of the aryl groups represented by Ar.sub.2 and Ar.sub.3
is independently preferably an aryl group having 6 to 30 carbon
atoms and more preferably an aryl group having 6 to 18 carbon
atoms. The aryl group may be substituted, and preferably an aryl
group having 6 to 18 carbon atoms which may have an alkyl group
having 1 to 4 carbon atoms or an aryl group having 6 to 18 carbon
atoms. Examples thereof may include a phenyl group, a naphthyl
group, a tolyl group, an anthryl group, a dimethylphenyl group, a
biphenyl group and the like, and a phenyl group or a naphthyl group
is preferred. n is preferably 0 or 1.
[0071] The alkyl group represented by Ar.sub.2 and Ar.sub.3 is
preferably an alkyl group having 1 to 6 carbon atoms, and more
preferably an alkyl group having 1 to 4 carbon atoms. Examples
thereof include a methyl group, an ethyl group, n-propyl group, an
isopropyl group, an n-butyl group, an isobutyl group and a t-butyl
group, and a methyl group or an ethyl group is preferred, and a
methyl group is more preferred.
[0072] Each of the heteroaryl group represented by Ar.sub.2 and
Ar.sub.3 is independently preferably a heteroaryl group having 3 to
30 carbon atoms, and more preferably a heteroaryl group having 3 to
18 carbon atoms. The heteroaryl group may be substituted, and
preferably a heteroaryl group having 3 to 18 carbon atoms which may
have an alkyl group having 1 to 4 carbon atoms or an aryl group
having 6 to 18 carbon atoms. In addition, the heteroaryl group
represented by Ar.sub.2 and Ar.sub.3 may be a condensed ring
structure, and preferably a condensed ring structure of a
combination of rings selected from a furan ring, a thiophene ring,
a selenophene ring, a silole ring, a pyridine ring, pyrazine ring,
a pyrimidine ring, an oxazole ring, a thiazole ring, a triazole
ring, a oxadiazole ring and a thiadiazole ring (the rings may be
the same as each other). A quinoline ring, an isoquinoline ring, a
benzothiophene ring, a dibenzothiophene ring, a thienothiophene
ring, a bithienobenzene ring and a bithienothiophene ring are
preferred.
[0073] The alkyl group represented by R.sub.1 to R.sub.6 is
preferably an alkyl group having 1 to 6 carbon atoms, and more
preferably an alkyl group having 1 to 4 carbon atoms. Examples
thereof include a methyl group, an ethyl group, n-propyl group, an
isopropyl group, an n-butyl group, an isobutyl group and a t-butyl
group, and a methyl group or an ethyl group is preferred, and a
methyl group is more preferred.
[0074] n is preferably 0 or 1.
[0075] Each of the heteroaryl group represented by R.sub.1 to
R.sub.6 is independently preferably a heteroaryl group having 3 to
30 carbon atoms, and more preferably a heteroaryl group having 3 to
18 carbon atoms. The heteroaryl group may be substituted, and
preferably a heteroaryl group having 3 to 18 carbon atoms which may
have an alkyl group having 1 to 4 carbon atoms or an aryl group
having 6 to 18 carbon atoms. In addition, a heteroaryl group
containing a 5-, 6- or 7-membered ring, or a condensed ring thereof
is preferred. The heteroatom contained in the heteroaryl group may
include an oxygen atom, a sulfur atom and a nitrogen atom. Specific
examples of the ring constituting the heteroaryl group may include
a furan ring, a thiophene ring, a pyrrole ring, a pyrroline ring, a
pyrrolidine ring, an oxazole ring, an isoxazole ring, a thiazole
ring, an isothiazole ring, an imidazole ring, an imidazoline ring,
an imidazolidine ring, a pyrazole ring, a pyrazoline ring, a
pyrazolidine ring, a triazole ring, a furazan ring, a tetrazole
ring, a pyran ring, a thiine ring, a pyridine ring, a piperidine
ring, an oxazine ring, a morpholine ring, a thiazine ring, a
pyridazine ring, a pyrimidine ring, a pyrazine ring, a piperazine
ring, a triazine ring, and the like.
[0076] Examples of the condensed ring may include a benzofuran
ring, an isobenzofuran ring, a benzothiophene ring, an indole ring,
an indoline ring, an isoindole ring, a benzoxazole ring, a
benzothiazole ring, an indazole ring, a benzimidazole ring, a
quinoline ring, an isoquinoline ring, a cinnoline ring, a
phthalazine ring, a quinazoline ring, a quinoxaline ring, a
dibenzofuran ring, a carbazole ring, a xanthene ring, an acridine
ring, a phenanthridine ring, a phenanthroline ring, a phenazine
ring, a phenoxazine ring, a thianthrene ring, a thienothiophene
ring, an indolizine ring, a quinolizine ring, a quinuclidine ring,
a naphthyridine ring, a furin ring, a pteridine ring and the
like.
[0077] Each of the aryl groups represented by R.sub.1 to R.sub.6 is
independently preferably an aryl group having 6 to 30 carbon atoms
and more preferably an aryl group having 6 to 18 carbon atoms. The
aryl group may be substituted, and preferably an aryl group having
6 to 18 carbon atoms which may have an alkyl group having 1 to 4
carbon atoms or an aryl group having 6 to 18 carbon atoms. Examples
thereof may include a phenyl group, a naphthyl group, an
anthracenyl group, a pyrenyl group, a phenanthrenyl group, a
methylphenyl group, a dimethylphenyl group, a biphenyl group and
the like, and a phenyl group, a naphthyl group or an anthracenyl
group is preferred.
[0078] Any of adjacent Ar.sub.1, Ar.sub.2, Ar.sub.3 and R.sub.1 to
R.sub.6 may be linked to each other to form a ring, and preferred
examples of the formed ring may include a cyclohexene ring, a
cyclopentene ring, a benzene ring, a naphthalene ring, a thiophene
ring, a pyrene ring and the like.
[0079] In the case where Ar.sub.2, Ar.sub.3 and R.sub.1 to R.sub.6
have a substituent, examples of the substituent may include a
halogen atom, an alkyl group (including a methyl group, an ethyl
group, an n-propyl group, an isopropyl group, a t-butyl group a
cycloalkyl group, a bicycloalkyl group, and a tricycloalkyl group),
an alkenyl group (including a cycloalkenyl group, and a
bicycloalkenyl group), an alkynyl group, an aryl group, a
heterocyclic group (which may also be called a heterocyclic group),
a cyano group, a hydroxy group, a nitro group, a carboxy group, an
alkoxy group, an aryloxy group, a silyloxy group, a heterocyclic
oxy group, an acyloxy group, a carbamoyloxy group, an
alkoxycarbonyl group, an aryloxycarbonyl group, an amino group
(including an anylino group), an ammonio group, an acylamino group,
an aminocarbonylamino group, an alkoxycarbonylamino group, an
aryloxycarbonylamino group, a sulfamoylamino group, an alkyl and
arylsulfonylamino group, a mercapto group, an alkylthio group, an
arylthio group, a heterocyclic thio group, a sulfamoyl group, a
sulfo group, an alkyl and arylsulfinyl group, an alkyl and
arylsulfonyl group, an acyl group, an aryloxycarbonyl group, an
alkoxycarbonyl group, a carbamoyl group, an aryl and heterocyclic
azo group, an imide group, a phosphino group, a phosphinyl group, a
phosphinyloxy group, a phosphinylamino group, a phosphono group, a
silyl group, a hydrazino group, a ureide group, a boric acid group
(--B(OH).sub.2), a phosphate group (--OPO(OH).sub.2), a sulfate
group (--OSO.sub.3H), and other known substituents.
[0080] Specific examples of the compound represented by Formula (1)
will be described below, but the present invention is not limited
thereto.
##STR00002## ##STR00003##
[0081] An electron donating organic material may be used in the
electron blocking layer 107b. Specifically, an aromatic diamine
compound such as
N,N-bis(3-methylphenyl)-1,1'-biphenyl)-4,4'-diamine (TPD) or
4,4'-bis[N-(naphthyl)-N-phenyl-amino]biphenyl (.alpha.-NPD), a
polyphirine compound such as oxazole, oxadiazole, triazole,
imidazole, imidazolone, a stilbene derivative, a pyrazoline
derivative, tetrahydroimidazole, polyarylalkane, butadiene,
4,4',4''-tris(N-(3-methylphenyl)N-phenylamino)triphenylamine(m-MTDATA),
porphine, tetraphenylporphine copper, phthalocyanine, copper
phthalocyanine, and titanium phthalocyanineoxide, a triazole
derivative, an oxadiazole derivative, an imidazole derivative, a
polyarylalkane derivative, a pyrazoline derivative, a pyrazolone
derivative, a phenylenediamine derivative, an anileamine
derivative, an amino substituted calcone derivative, an oxazole
derivative, a styrylanthracene derivative, a fluorenone derivative,
a hydrazone derivative, and a silazane derivative may be used as a
low molecular material, and a polymer such as phenylenevinylene,
fluorene, carbazole, indole, pyrene, pyrrole, picholine, thiophene,
acetylene, and diacetylene or a derivative thereof may be used as a
polymer material. Any compound having a sufficient hole transport
property may be used even though the compound is not an electron
donating compound.
[0082] An inorganic material may be used as the electric charge
blocking layer 107b. In general, the dielectric constant of an
inorganic material is larger than that of an organic material, and
therefore, when the inorganic material is used for the electron
blocking layer 107b, a large quantity of voltage is applied to the
photoelectric conversion layer 107a, thereby enabling to increase
the photoelectric conversion efficiency. Examples of the material
that may form the electric charge blocking layer 107b include
calcium oxide, chromium oxide, chromiumcopper oxide, manganese
oxide, cobalt oxide, nickel oxide, copper oxide, galliumcopper
oxide, strontiumcopper oxide, niobium oxide, molybdenum oxide,
indiumcopper oxide, indiumsilver oxide, iridium oxide and the
like.
[0083] In the electric charge blocking layer 107b including a
plurality of layers, among the plurality of layers, the layer
adjacent to the photoelectric conversion layer 107a is preferably a
layer containing the same material as the p-type organic
semiconductor contained in the photoelectric conversion layer 107a.
By using the same p-type organic semiconductor in the electron
blocking layer 107b, the formation of mid-level at the interface of
the layer adjacent to the photoelectric conversion layer 107a may
be suppressed, and thus, dark current may be further
suppressed.
[0084] In the case where the electric charge blocking layer 107b is
a single layer, the layer may be formed of an inorganic material,
and in the case where the electric charge blocking layer is formed
of a plurality of layers, one or two or more layers may be formed
of an inorganic material.
[0085] It is preferred to use compounds represented by the
following Formula (1-A1) or Formula (1-A2) as a material used in
the electric charge blocking layer 107b.
##STR00004##
[0086] In Formula (1-A1) and Formula (1-A2), R.sub.1 and R.sub.2
each independently represent a heterocyclic group that may be
substituted by an alkyl group. X.sub.1 and X.sub.2 each
independently represent a carbon atom, a nitrogen atom, an oxygen
atom, a sulfur atom, and a silicon atom, and may further have a
substituent. L may represents a single bond, an oxygen atom, a
sulfur atom, an alkylene group, an alkenylene group, a
cycloalkylene group, a cycloalkenylene group, an arylene group, a
divalent heterocyclic group or an imino group, which may further
have a substituent. n.sub.1 and n.sub.2 each independently
represent an integer of 1 to 4.
[0087] The heterocyclic group represented by R.sub.1 and R.sub.2
may include a condensed ring formed of 2 to 5 single rings.
Further, the number of carbon atoms is preferably 6 to 30, and more
preferably 6 to 20.
[0088] In addition, the alkyl group that may be substituted by the
heterocyclic group is preferably an alkyl group having 1 to 6
carbon atoms, and may be a straight- or branched-chained alkyl
group, or a cycloalkyl group, and a ring (for example, a benzene
ring) formed by bonding a plurality of alkyl groups, but preferably
branched-chained alkyl group. Specific examples of the alkyl group
may include a methyl group, an ethyl group, an isopropyl group, a
t-butyl group, and a neopentyl group, and a t-butyl group is
preferable.
[0089] L represents a single bond, an oxygen atom, a sulfur atom,
an alkylene group, an alkenylene group, a cycloalkylene group, a
cycloalkenylene group, an arylene group, a divalent heterocyclic
group or an imino group. L is preferably a single bond, an alkylene
group having 1 to 12 carbon atoms, an alkenylene group having 2 to
12 carbon atoms (for example, --CH.sub.2.dbd.CH.sub.2--), an
arylene group having 6 to 14 carbon atoms (for example, a
1,2-phenylene group, and a 2,3-naphthylene group), a heterocyclic
group having 4 to 13 carbon atoms, an oxygen atom, a sulfur atom,
and an imino group (for example, a phenylimino group, a methylimino
group, and a t-butylimino group) having a hydrocarbon group having
1 to 12 carbon atoms (preferably an aryl group or alkyl group),
more preferably a single bond, an alkylene group having 1 to 6
carbon atoms (for example, a methylene group, a 1,2-ethylene group,
and a 1,1-dimethylmethylene group), an oxygen atom, a sulfur atom,
and an imino group having 1 to 6 carbon atoms, and particularly
preferably a single bond or an alkylene group having 1 to 6 carbon
atoms.
[0090] In the case where L represents an alkylene group, an
alkenylene group, a cycloalkylene group, a cycloalkenylene group,
an arylene group, a divalent heterocyclic group or an imino group,
examples thereof may further have a substituent. Examples of the
added substituent may include an alkyl group, a halogen atom, an
aryl group, and a hetero ring.
[0091] Examples of the heterocyclic group that may be substituted
by the alkyl group represented by R.sub.1 and R.sub.2 may include
the following N1 to N15. N13 is preferable.
##STR00005## ##STR00006## ##STR00007## ##STR00008##
[0092] An alkyl group or an aryl group is preferable as the
substituent of X.sub.1 and X.sub.2.
[0093] The alkyl group is preferably an alkyl group having 1 to 4
carbon atoms, examples thereof may include a methyl group, an ethyl
group, an n-propyl group, an isopropyl group or a t-butyl group,
and a methyl group is more preferable.
[0094] The aryl group is preferably an aryl group having 6 to 20
carbon atoms. The aryl group may be substituted, and preferably an
aryl group having 6 to 15 carbon atoms which may have an alkyl
group having 1 to 4 carbon atoms. Examples thereof may include a
phenyl group, a naphthyl group, an anthracenyl group, a
9-dimethylfluorenyl group, a methylphenyl group, a dimethylphenyl
group and the like, and a phenyl group, a naphthyl group, an
anthracenyl group and a 9-dimethylfluorenyl group are
preferred.
[0095] Materials represented by the following Formulas are
particularly preferred as the material of the electric charge
blocking layer.
##STR00009## ##STR00010## ##STR00011##
[0096] The solid-state imaging device 100 constituted as described
above is manufactured as follows.
[0097] First, as illustrated in FIG. 1, the substrate 101 is
provided with the dielectric layer 102 which includes the
connection portion 105, 106, and the film of a material of the
pixel electrode 104 is formed on the dielectric layer 102 of the
substrate 101 by, for example, a sputtering method.
[0098] Next, patterning of the film of the pixel electrode material
is performed by photolithography and etching so that the film of
the pixel electrode material remains on the connection portion 106,
105, and then, a plurality of the pixel electrodes 104 and a
plurality of the connection electrodes 103 are formed.
[0099] After forming the plurality of pixel electrodes 104 and the
plurality of connection electrodes 103, a dielectric film is formed
thereon and planarized to obtain the dielectric layer 102
illustrated in FIG. 2. It is preferred that the process up to this
point is performed in a vacuum.
[0100] A photoelectric conversion device used in a solid-state
imaging device is a small device, as compared to a solar cell. As
the size of one pixel electrode is small, it is difficult to adopt
a laser patterning as disclosed in Patent Document 5. Accordingly,
in the present manufacturing method, the pixel electrode 104 is
formed by photolithography and etching. Further, by forming the
pixel electrode in a vacuum, foreign matters such as moisture and
oxygen, which are factors in deteriorating a light receiving layer
when forming an electrode, are prevented from being attached to the
substrate.
[0101] Subsequently, the substrate 101 is heated at 270.degree. C.
or above. The heating of the substrate 101 may be performed either
in a vacuum or in the atmosphere.
[0102] After the heating of the substrate 101 is completed, the
light receiving layer 107, the counter electrode 108, the buffer
layer 109, the sealing layer 110, the color filter 111 and the
protection layer 114 are formed in this order to obtain the
solid-state imaging device 100.
[0103] By the method, deterioration of the pixel electrode 104 in
the heating process performed after the photoelectric conversion
layer is formed can be prevented, and thus, heat resistance of the
solid-state imaging device 100 is improved.
[0104] Hereinafter, the effects of the present invention will be
described based on the examples.
EXAMPLES
Example 1
[0105] 15 nm of Titanium oxide nitride (TiON) film was formed by a
sputtering method on the CMOS substrate having a signal reading
circuit, of which an SiO.sub.2 dielectric film was formed on the
surface (including a connection portion), and then, patterning of
the film was performed by photolithography and dry etching to form
a pixel electrode. The process up to this point was performed in a
vacuum. Further, the pixel electrode was electrically connected to
the signal reading circuit in the substrate through the connection
portion in the dielectric film. Thereafter, the substrate was
heated at 300.degree. C. for 30 minutes in the atmosphere
(substrate heating process).
[0106] Then, the following compound 2 was formed in a film
thickness of 100 nm on the substrate by a vacuum thermal
evaporation method to form an electron blocking layer. Thereafter,
a film of the following compound 1 and C.sub.60 was formed by
co-deposition in a volume ratio of 1:2 to form a photoelectric
conversion layer.
[0107] Subsequently, an ITO film was formed in a thickness of 10 nm
by a sputtering method to form a counter electrode. Then, a film of
alumina was formed in a thickness of 200 nm on the counter
electrode by an ALCVD method to form a buffer layer. Thereafter, a
film of silicon oxynitride was formed in a thickness of 100 nm on
the buffer layer by a sputtering method to form a sealing layer. In
this manner, the solid-state imaging device was manufactured having
a constitution of up to a sealing layer as illustrated in FIG.
1
Examples 2 to 8
[0108] A solid-state imaging device was manufactured in the same
manner as in Example 1, except that a material of the electron
blocking layer, a material of the photoelectric conversion layer, a
heating temperature in the substrate heating process and a material
of the pixel electrode were changed as shown in Table 1 (also
different from Example 1 in that in Examples 3 and 4, ITO was used
as the pixel electrode material). With respect to the mark "**/***"
in the column of a constitution of the light receiving layer in
Table 1, ** represents an electron blocking layer and ***
represents a photoelectric conversion layer.
Comparative Example 1
[0109] A solid-state imaging device was manufactured in the same
manner as in Example 1 except that the substrate heating process
was omitted.
Comparative Examples 2 to 5
[0110] A solid-state imaging device was manufactured in the same
manner as in Comparative example 1, except that a material of the
electron blocking layer, a material of the photoelectric conversion
layer and a material of the pixel electrode were changed as shown
in Table 1 (also different from Comparative example 1 in that in
Comparative example 2, ITO was used as the pixel electrode
material).
Comparative Example 6
[0111] A solid-state imaging device was manufactured in the same
manner as in Comparative example 1, except that a heating
temperature in the substrate heating process was changed to
250.degree. C.
Comparative Example 7
[0112] A solid-state imaging device was manufactured in the same
manner as in Comparative example 1, except that a heating
temperature in the substrate heating process was changed to
260.degree. C.
TABLE-US-00001 Dark current Concentration of Concentration of
density after oxygen in nitride in annealing at the thickness the
thickness Concentration of Concentration of 220.degree. C. (a of 10
nm from the of 10 nm from the oxygen in nitride in relative
substrate side substrate side the entire the entire value when of
pixel electrode of pixel electrode pixel electrode pixel electrode
the value (atm % to Ti) (atm % to Ti) (atm % to Ti) (atm % to Ti)
immediately Constitution Pixel Sub- At the After At the After At
the After At the After after of light elec- strate time of
substrate time of substrate time of substrate time of substrate
manufacturing receiving trode heating forming heating forming
heating forming heating forming heating each layer material process
electrode process electrode process electrode process electrode
process device is 1) Ex. 1 Compound 2/ TiON 300.degree. C. 29% 46%
101% 87% 70% 88% 83% 71% 0.48 Compound 1 + 30 min. C.sub.60 Ex. 2
Compound 2/ TiON 350.degree. C. 29% 71% 101% 75% 70% 107% 83% 61%
0.47 Compound 1 + 30 min. C.sub.60 Ex. 3 Compound 2/ ITO
300.degree. C. -- -- -- -- -- -- -- -- 1.00 Compound 1 + 30 min.
C.sub.60 Ex. 4 Compound 2/ ITO 350.degree. C. -- -- -- -- -- -- --
-- 0.56 Compound 1 + 30 min. C.sub.60 Ex. 5 Compound 3/ TiON
300.degree. C. 29% 46% 101% 87% 70% 88% 83% 71% 0.43 Compound 1 +
30 min. C.sub.60 Ex. 6 Compound 2/ TiON 300.degree. C. 29% 46% 101%
87% 70% 88% 83% 71% 0.94 Compound 4 + 30 min. C.sub.60 Ex. 7
Compound 2/ TiON 300.degree. C. 29% 46% 101% 87% 70% 88% 83% 71%
0.30 Compound 5 + 30 min. C.sub.60 Ex. 8 Compound 2/ TiON
280.degree. C. 29% 41% 101% 88% 70% 81% 83% 72% 0.57 Compound 1 +
30 min. C.sub.60 Comp. Compound 2/ TiON none 29% -- 101% -- 70% --
83% -- 3.44 Ex. 1 Compound 1 + C.sub.60 Comp. Compound 2/ ITO none
-- -- -- -- -- -- -- -- 24.6 Ex. 2 Compound 1 + C.sub.60 Comp.
Compound 3/ TiON none 29% -- 101% -- 70% -- 83% -- 3.33 Ex. 3
Compound 1 + C.sub.60 Comp. Compound 2/ TiON none 29% -- 101% --
70% -- 83% -- 4.18 Ex. 4 Compound 4 + C.sub.60 Comp. Compound 2/
TiON none 29% -- 101% -- 70% -- 83% -- 3.13 Ex. 5 Compound 5 +
C.sub.60 Comp. Compound 2/ TiON 250.degree. C. 29% 34% 101% 92% 70%
72% 83% 76% 2.02 Ex. 6 Compound 1 + 30 min. C.sub.60 Comp. Compound
2/ TiON 260.degree. C. 29% 36% 101% 92% 70% 73% 83% 74% 1.61 Ex. 7
Compound 1 + 30 min. C.sub.60 ##STR00012## ##STR00013##
##STR00014## ##STR00015##
[0113] With respect to the photoelectric conversion device in
Examples 1, 2 and 5 to 8, and in Comparative examples 6 and 7, the
composition of the pixel electrode before and after the substrate
heating process before forming the light receiving layer was
measured. With respect to the photoelectric conversion device in
Comparative examples 1 and 3 to 5, the composition of the pixel
electrode before forming the light receiving layer was measured.
The results are shown in Table 1 for reference.
[0114] Further, with respect to all solid-state imaging devices, a
dark current density was measured by applying an electric field of
2.0.times.10.sup.5 V/cm to the side of the pixel electrode in minus
direction. The dark current density was measured in each case after
completing the manufacture of a solid-state imaging device and
after heating the solid-state imaging device at 220.degree. C. for
30 minutes, which is the same temperature as in the heating process
performed later. The results measured after the heating were shown
in Table 1 as a relative value to the results measured before the
heating.
[0115] As shown in Table 1, the solid-state imaging device in
Examples 1 to 8 had a lower dark current density by performing the
heating process, as compared with the solid-state imaging device in
Comparative examples 1 to 5 in which the substrate heating process
was omitted, and it can be understood that heat resistance is
improved by the substrate heating process.
[0116] Further, the dark current was substantially decreased in
Example 8 where the pixel electrode is heated at 280.degree. C., as
compared with Comparative example 7 where the pixel electrode is
heated at 260.degree. C. From the result, it can be seen that heat
resistance can be improved when performing the heating of pixel
electrode at the temperature of 270.degree. C. or above.
[0117] The amount of oxygen in the pixel electrode measured for the
solid-state imaging device in Comparative examples 6 and 7 was
increased no more than 10% before and after the substrate heating
process. Meanwhile, in Examples 1, 2 and 5 to 8, the amount of
oxygen was increased as much as 10% or more. From the result, it
can be assumed that in the case of a pixel electrode formed of
TiON, the amount of oxygen in the pixel electrode is increased by
10% or more by performing the substrate heating process, and as a
result, the increase in the amount of oxygen in the pixel electrode
during the heating process is prevented, thereby preventing
deterioration of the pixel electrode.
[0118] Further, the above Examples only show the data in the case
of heating the pixel electrode for 30 minutes, but the same effect
could be obtained even though the heating time was changed.
[0119] As described above, the following is disclosed in the
present specification.
[0120] The present invention relates to a method for manufacturing
a photoelectric conversion device which includes: a first electrode
in which a dielectric film composed of an oxide film is formed on a
substrate, the first electrode including a conductive material
formed on the dielectric film; a light receiving layer that
includes an organic material formed on the fist electrode; and a
second electrode which is formed on the light receiving layer, in
which the method includes: a first process for forming the first
electrode on the dielectric film; a second process for forming the
light receiving layer on the first electrode; a third process for
forming the second electrode on the light receiving layer; and a
heating process for heating the substrate at 270.degree. C. or
above, the heating process performed before the second process and
after the first process.
[0121] In the method for manufacturing the photoelectric conversion
device, the first process includes: a film forming process of a
conductive material on the dielectric layer; and a patterning
process of a formed film of the conductive material.
[0122] In the method for manufacturing the photoelectric conversion
device, the patterning process is performed in a vacuum.
[0123] In the method for manufacturing the photoelectric conversion
device, the patterning process is performed by photolithography and
etching.
[0124] In the method for manufacturing the photoelectric conversion
device, the light receiving layer includes: an electric charge
blocking layer that includes an organic material; and a
photoelectric conversion layer that includes an organic layer.
[0125] In the method for manufacturing the photoelectric conversion
device, the conductive material is ITO or TiON.
[0126] In the method for manufacturing the photoelectric conversion
device, the conductive material is TiON, and atomic % of an oxygen
amount contained in the first electrode to a titanium amount is
increased by 10% or more before and after the heating process.
[0127] A solid-state imaging device includes: a photoelectric
conversion device manufactured by the method for manufacturing the
photoelectric conversion device; and a signal reading circuit
formed on the substrate, the signal reading circuit capable of
reading out the signal according to the quantity of electric
charges collected in the first electrode.
[0128] The imaging apparatus includes the solid-state imaging
device.
INDUSTRIAL APPLICABILITY
[0129] According to the present invention, there may be provided a
method for manufacturing a photoelectric conversion device having a
light receiving layer that includes an organic material, in which
heat resistance can be improved irrespective of a material of a
light receiving layer. Further, there may be provided a solid-state
imaging device having a photoelectric conversion device
manufactured by the manufacturing method, and an imaging apparatus
having the solid-state imaging device.
[0130] The present invention has been described in detail with
reference to specific embodiments, but it is apparent to the person
with ordinary skill in the art that various changes or
modifications may be made without departing from the spirit and the
scope of the present invention.
[0131] The present application is based on Japanese Patent
Application (Patent Application No. 2010-216104) filed on Sep. 27,
2010, and Japanese Patent Application (Patent Application No.
2011-169649) filed on Aug. 2, 2011, and the contents of which are
incorporated herein by reference.
EXPLANATION OF REFERENCE NUMERALS
[0132] 100: Solid-state imaging device [0133] 101: Substrate [0134]
102: Dielectric layer [0135] 104: Pixel electrode [0136] 107: Light
receiving layer [0137] 100: Counter electrode
* * * * *